I have an original IBM PC in storage somewhere. I demand compatibility with Unreal Engine 4. There is no hard disk, but it comes with two 5-1/4 floppy drives. My current github directory for unreal is 98.8GB that is only 274,444 double density floppy disks. Sounds manageable. (totally)
I was able to get Prince of Persia to run on it once. I want to use UE4 on it. Make it happen.